Lubricating greases

ABSTRACT

COPPER CORROSION RESITANT GREASE ARE OBTAINED BY INCORPORATING THEREIN A MINOR AMOUNT OF A 3-AMINO-1,2,4TRIAZOLE.

3,663,436 LUBRICATING GREASES William D. Carswell, Chester, England, asslgnor to Shell Oil Company, New York, N.Y.

No Drawing. Filed June 27, 1968, Ser. No. 740,487 Claims priority, application Great Britain, July 13, 1967, 32,205/ 67 Int. Cl. Cm 3/26 US. Cl. 25228 6 Claims ABSTRACT OF THE DISCLOSURE Copper corrosion resistant greases are obtained by incorporating therein a minor amount of a 3-am1no-1,2,4- triazole.

This invention relates to lubricating greases containing certain triazoles as metal deactivators. More specifically, this invention relates to a lubricating grease comprising a lubricating oil, a thickener, and a minor proportion of a 1,2,4-triazole.

A disadvantage of many greases when in contact with a metal surface containing copper for a period of time at normal or moderate temperatures, i.e., about 60 C., is that the grease turns green and stains the metal. This is particularly true with certain clay greases containing premade waterproofed clay powders as a thickener, especially when glycerol is incorporated therein as an anti-wear agent. Furthermore, at high temperatures, e.g., 100l20 C., the grease darkens thereby masking the greening and allowing appreciably more staining to occur on the metal.

It has now been found that the addition of certain 1,2,4- triazoles to greases considerably reduces the amount of greening and/or darkening of the grease thereby lessening the staining of metal surfaces at normal and elevated temperatures. Furthermore, the addition of 1,2,4-triazoles to greases having glycerol incorporated therein, such as clay greases prepared by the wet process and lithium greases, greatly reduces the staining of metals containing copper at elevated temperatures.

The 1,2,4-triazoles which are useful in this invention are preferably 3-amino-l,2,4-triazoles having the formula N I-|I N Ell L L...

and 3-amino-5-heptyl-1,2,4-triazole, i.e.

NNH II 3,663,436 Patented May 16, 1972 but also acylated and aroylated-1,2,4-triazoles which may be:

N-N Ti i ii-NHCORi wherein R is a member selected from the group consisting of alkyl and aryl.

Preferable triazoles are those in which R R and R are hydrogen atoms. Preferably, when R R and R are not all hydrogen atoms, the desired number of carbon atoms in the R groups is less than 30 and preferably less than 7.

The 3-aminol,2,4-triazoles of this invention can be used in any desired proportion. Generally proportions of about 0.00l2% by weight are used and concentrations of from about 0.1 to 0.5% by weight based on the total composition are preferred.

The base oils of the grease can be either synthetic lubricating oils or mineral lubricating oils. Synthetic oils such as diesters, complex esters, polysiloxanes, and polyphenylethers may be used. It is, however, preferred to use a mineral lubricating oil.

The thickener can be either organic or inorganic thickeners. Among the organic thickeners are the soaps, such as the alkali and alkaline earth metal salts of fatty acids, e.g., lithium hydroxystearate. It is preferred, however, to use an inorganic thickener and more preferably an oleophilic clay, i.e., a clay that has been rendered Waterproof by the addition of a surfactant thereto.

Suitable clays have a substantial base exchange capacity of normally at least 25 milliequivalents (meq.) per grams, preferably between 25 and 100 meq. per 100 grams. Particularly useful are the montmorillonite clays, and in particular those referred to as bentonites. The magnesium bentonites sometimes referred to as hectorites are particularly useful.

The clay can be made oleophilic by absorption thereon or reaction thereon with organic ammonia bases or their salts. Preferably, the clay is made oleophilic by coating with a cationic surface-active agent. Preferred surfaceactive agents or waterproofants are amino amides formed between aliphatic saturated or unsaturated monocarboxylic acids having 10 to 22 carbon atoms and alkylene polyamines. The alkylene polyamines are usually the bottoms products remaining from the manufacture of ethylene diamine, i.e., diethylene triamine and tetraethylene pentamine.

These waterproofants may be used in the proportion of 35125% w. based on the clay, and the clay may be present in the grease in the proportion of about 2.5 to 10% w. based on the total grease compositions.

In addition to the 1,2,4-triazoles, other additives may be present in the grease, such as anti-wear agents, e.g.,

glycerol, castor oil, antioxidants, e.g., aromatic amines and anti-corrosion agents, e.g., alkaline metal nitrites and extreme pressure agents, e.g., lead naphthenates or metal sulfides.

method, e.g. tray dried or (3) a small proportion of a mineral lubricating oil is added to the composition which is then filtered and dried.

The clay product is mixed with a lubricating oil in order The greases may be prepared by either a wet or to prepare the grease. Preferably the mixture is sheared powdered process. at normal or elevated temperatures, e.g., 80 C., and Thus in the wet process, the clay can be dispersed any additives, such as the 1,2, 4-tr1azoles are normally in water to form a 1-5% w. clay dispersion from which added together w1th the lubricating 011 (powder process the gangue may be separated by sedimentation or centri- Since the present tnagoles are relatively insoluble in fuging. The waterproofant, optionally 4-l2% w. basis mineral 0118 y y he Incorporated 1n h 0115 by means clay, of a strong mineral acid such as phosphoric acid, of solvents such as ethylene glycol, dlethylene glycol, and at least part of the mineral oil are then added while g y 01 and Water at I10 fma1 of elevated thmperaml'es agitating. An oil layer containing the olephilic clay then (e.g., 80 C.) and at hlgh concentrations (e.g., as a separates from the water. The free water is removed and 5 /50% W. S0111t 10n). Although these concentrates are the clay/oil layer is heated to evaporate substantially any not Soluble 1h mlheral y can he dlsPefsect y 7' remaining water. The components are subjected to a high fin ly so t at the fofmatlon of coarse partlcles ln the rate of shear either during water evaporation or b. grease is prevented. In some cases thetnazoles preclpitated sequent thereto, and any remaining desired lubricating oil 01115 of the 'Sohlhoh h hg- Thls, however, did not and any additives such as the 1,2,4-triazo1es are added in pp Q reduce then eflectlvehess 0r Produce coarse this final stage (wet process). 0 ParttcteF h f t Sometimes the preparation of the grease from a pre- The lhvfihtloh 15 Illustrated y the follPvYlhg dataformed waterproofed clay powder is preferred. The hectoflfe y- E comalhlhg the 31111110 degangued aqueous clay dispersion containing from 15% amide reactloh P d Of a mlXture of alkylene poly w. of clay and having a base exchange capacity of beamlhes and aclds was P p y both t Wet tween and 100 meq. of exchangeable base per 100 25 and the P P All thh grfiases comalh at least grams of clay is mixed with -125 W. based on the 05% -s clay of a waterproofant, optionally 442% w. basis clay, The triazoles were dissolved in a suitable solvent at of a strong mineral acid such as phosphoric acid, and 80 to Obtam a cottcenttater whlch added to the 500 to 5000% w. based on the clay of a water-immiscible grease before homogemzatlon or the fimshett greaserelatively volatile inert organic liquid, mg. a naphtha 30 The greases were then tested 1n a brass disc test as having a boiling range of 230-300 F. or a kerosine havtonowsing a boiling range of 330-390 F. or their mixtures. A brass 38 d1amter was Pottshtd wlth There is formed a base consisting of the clay, watercarbomndum Powder t cleaned wlth Cotton W A proofant and a minor proportion of water associated with layer of grease dlatneter and 1 thlck was the organic liquid together with a phase consisting of a SPrtjad on f and the (its? then Platd an oven major proportion of water. The latter phase is removed dunng a tiertam tune at a certam tfmpetatuteand the remaining water and organic liquid are volatilized The greenmg the grease at60 the darktnfng of by heat. There is thus formed a pulverulent or crumbly the grease at 100 and 120 and the Stammg 0t oleophilic clay prdouct. A proportion of a lubricating oil, the dlscs Ware then noted as follows: preferably 50200% w. based on clay may be mixed 40 none 3 modemte with the clay PI'lOI to evaporation of water and volatile Hevere liquid. The presence of the lubricating oil at this stage 2 s1ight severe promotes the maintenance of high thickening power of the clay product. As the proportion of lubricating oil is The results are given in the following table (the first increased dispersal of the product in any medium at a figure represents greening at C. or darkening at 100 later stage (such as in oil for the formation of grease) C. and 120 C., the second figure staining; percentages are becomes progressively easier. by weight; EG=ethylene glycol, DEG=diethylene glycol,

Alternatively a preformed clay power is obtained by G=glycerol). heating a degangued clay dispersion in water at C. r The results indicate that overall the 1,2,4-triazoles are and adding, while stirring, the waterproofant, optionally superior to the 1,2,3-triazoles and benzotriazoles espea strong mineral acid such as phosphoric acid, to facilitate cially at elevated temperatures of C. and C. the coating of the clay surface. Thereafter the composition Furthermore better results are obtained with the 3-amino may be ,(1) spray dried to a powder containing 1 to 4% 1,2,4-triazoles at all temperatures and at lower concenwater or (2) filtered and then dried by any convenient trations.

TABLE Concentration Additive in1 Powder process Wet process S01- 60 100C. 120 0. 100C. 120C. Solvent, Grease, (2O (24 (24 (24 (24 Additive vent percent percent hours) hours) hours) hours) hours) Bonzotrlazole EG- 60 0.3 1-1 DEG 60 0.1 4-2 DEG 50 0. a 1-1 3-3 4-4 2-1 3-2 G 50 0.1 3-2 3-5 4-4 G 50 0. 3 1-0 3-3 4-4 2-2 5-4 fi-iiiothylbonzotriazolo EG- 50 0.3 1-1 DEG 50 0.1 3-2 3-4 DEG 50 0.3 1-1 3-1 G 50 0.1 3-2 3-1 G 50 0.3 1-0 3-1 5-lauryl benzotriazole DEG 50 0.1 4-3 3-4 DEG 50 0.3 1-1 3-0 TABLE-Continued Concentration Additive in- Powder process Wet process 801- 60 C. 100 0. 120 0. 100 0. 120 C. 801- vent, Grease, (24 (24 24 (24 Additive vent percent percent hours) hours) hours) hours) hours) 3-ami11o 1,2,4-triazole 60 0.1 -1 1-1 D E G 33 0. 1-0 2-1 D E G 50 0. 1 1-0 2-1 G 50 0. 05 0-1 2-2 G 60 0. 1 0-0 1-1 1,2,3-trlazole G 33 O. 1 1-2 3-2 G 33 0.3 0-0 3-3 1,2,4-trlazole. G 0 0- 1 4-4 3-3 4-3 G 50 0. 3 0-4 1-2 3-2 None 4-3 4-5 5-5 4-4 5-5 1 Water I claim as my invention:

1. A grease composition comprising a lubricating oil gelled to grease consistency by a thickener selected from the group consisting of metal soaps and oleophilic clays and containing a copper corrosion-reducing amount of a 1,2,4-triazole of the formula 6. A grease composition according to claim 5 wherein the clay is a performed coated powder.

References Cited UNITED STATES PATENTS 2,618,605 11/1952 Schaefi'er 252-390 3,3 82,087 5/ 1968 Ostrowski 252-390 2,890,170 6/ 1959 Rag'borg 25 2-50 3,006,848 10/ 1961 Caruso 25 2-28' 3,050,463 8/ 1962 Peterson 2 52-28 3,179,590 4/1965 Loefiier et a1 252-28 3,183,241 5/1965 Oja 252-49.5

FOREIGN PATENTS 1,041,334 9/1966 Great Britain 252-21 DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R. 

